docs: establish simulation architecture gate

docs/BUILD_IN_PUBLIC_PLAN.md

@@ -9,6 +9,10 @@ The immediate visual goal is to replace the flat prototype presentation with a
 small, attractive, watchable environment while preserving the working NPC
 simulation, player controls, UI, task lifecycle, and navigation behavior.
 
+This is a scoped visual-production plan. Milestone order and architecture gates
+are owned by [the learning roadmap](LEARNING_ROADMAP.md); simulation authority
+is governed by [ADR 0001](decisions/0001-simulation-authority-boundary.md).
+
 Before runtime terrain integration, food and wood should migrate from abstract
 zones to actual finite world objects according to
 [the ResourceNode migration plan](RESOURCE_NODE_MIGRATION.md). This prevents the
@@ -62,9 +66,9 @@ Main
 └── UI
 ```
 
-The player and `WorldViewManager` reference the task markers through exported
-`NodePath` values. `NpcVisual` relies on the navigation map to reach those
-markers.
+The player and `WorldViewManager` still reference non-resource activity markers
+through exported `NodePath` values. `NpcVisual` relies on the navigation map to
+reach both those markers and ResourceNode interaction points.
 
 Replacing the ground without respecting those references would break behavior
 that already works.
@@ -89,9 +93,7 @@ Main
 │   │   └── ResourceNodes
 │   │       ├── BerryBush instances
 │   │       └── Tree instances
-│   ├── LegacyTaskMarkers              temporary migration fallback
-│   │   ├── FarmZone                   fallback only
-│   │   ├── ForestZone                 fallback only
+│   ├── LegacyTaskMarkers              temporary non-resource activities
 │   │   ├── FoodZone
 │   │   ├── GuardZone
 │   │   ├── StudyZone
@@ -250,7 +252,7 @@ This becomes both a regression reference and excellent before/after material.
 There is a reproducible baseline showing the existing flat prototype and its
 working behaviors.
 
-### Systems prerequisite — Migrate food and wood targets
+### Systems prerequisite — Migrate food and wood targets ✅ complete
 
 Implement and validate the first ResourceNodes on the current flat map before
 moving the playable runtime onto Terrain3D:
@@ -263,7 +265,7 @@ moving the playable runtime onto Terrain3D:
 - extraction after work completion;
 - depletion and replanning;
 - actual extracted amount applied to the village;
-- zone fallback with visible warnings.
+- player interaction through the same extraction contract.
 
 Keep the other task zones temporarily. Rest, eating, study, and patrol will
 eventually use activity, storage, or workstation targets rather than pretending
@@ -335,6 +337,29 @@ The final navigation bake still happens after terrain and props stabilize.
 One static frame contains the ridge landmark, roofs, river/waterfall, and
 village work area. A test agent can traverse the intended task loop.
 
+### Systems gate — Harden simulation authority
+
+After the scaffold, greybox, and navigation spike prove the world shape, pause
+visual production and complete the mandatory architecture gate from the
+learning roadmap:
+
+- deterministic clock and seeded randomness;
+- fixed-seed headless scenarios and final-state checksum;
+- versioned serializable NPC, village, and resource records;
+- resource amount and reservation authority outside scene nodes;
+- stable action/profession IDs and initial definitions;
+- separate action selection, execution, target resolution, and visual travel;
+- explicit active-position synchronization.
+
+Do not solve this by moving simulation ownership into `JajceWorld`. The
+environment remains a presentation and active-world query surface.
+
+### Exit condition
+
+The same scenario produces the same result without `main.tscn`; unloading a
+visual does not change authoritative state; current resource and movement
+behavior still pass regression tests.
+
 ### Phase 3 — Establish the beauty baseline
 
 Add only the highest-value presentation:
@@ -366,7 +391,7 @@ Once the world composition is stable:
 2. Disable or remove the old flat world only after the new instance is present.
 3. Place or move bushes and trees under
    `JajceWorld/WorldObjects/ResourceNodes` while preserving stable IDs.
-4. Reconnect remaining player and `WorldViewManager` fallbacks to markers under
+4. Reconnect only remaining non-resource activity markers under
    `JajceWorld/LegacyTaskMarkers`.
 5. Bake navigation for the new walkable area.
 6. Test each existing task from multiple spawn positions.
@@ -538,25 +563,25 @@ The follow-up milestone is complete when:
 - cinematic and debug views can show the same real scenario;
 - a repeatable public-demo clip shows an autonomous cause and consequence;
 - performance and navigation regressions are measured and documented.
+- the mandatory architecture gate passes before final beauty integration.
 
 ## Immediate implementation order
 
 1. Capture the current flat-map baseline.
-2. Implement and validate ResourceNodes on the flat map.
-3. Migrate food and wood; keep remaining zones as logged fallbacks.
-4. Create `JajceWorld.tscn`.
-5. Create dedicated Terrain3D data under `terrain/jajce/`.
-6. Create `JajceLookdev.tscn` and its beauty camera.
-7. Sculpt the ridge, river valley, terraces, and waterfall drop.
-8. Place ResourceNodes and only the still-required legacy markers.
-9. Block out the fortress, houses, mill, and bridge.
-10. Run the early navigation spike.
-11. Establish terrain materials, lighting, water, mist, and foliage.
-12. Capture “Jajce Lookdev 01.”
-13. Instance `JajceWorld` into `main.tscn`.
-14. Reconnect fallbacks, rebake navigation, and regression-test the simulation.
-15. Add profession/readability presentation.
-16. Capture “Simulation Garden 01.”
+2. Treat ResourceNode migration and player parity as complete.
+3. Create `JajceWorld.tscn` and dedicated Terrain3D data.
+4. Create `JajceLookdev.tscn` and its beauty camera.
+5. Greybox the ridge, river valley, terraces, and waterfall drop.
+6. Place ResourceNodes with stable IDs and only required activity markers.
+7. Block out the fortress, houses, mill, and bridge.
+8. Run the early navigation spike.
+9. Pass the mandatory architecture gate before beauty production.
+10. Establish terrain materials, lighting, water, mist, and foliage.
+11. Capture “Jajce Lookdev 01.”
+12. Instance `JajceWorld` into `main.tscn`.
+13. Reconnect activity markers, rebake navigation, and run regression scenarios.
+14. Add profession/readability presentation and the reason inspector.
+15. Capture “Simulation Garden 01.”
 
 Do not start with GIS data, a full city, a large asset pack, or more NPC
 mechanics. The next proof is a beautiful stage for the systems that already